Large-scale mainframe computers continue to be used extensively across many industries. Historically, tape storage has been used to provide permanent and temporary to data protection services to those mainframes. In such environments, it is not uncommon for mainframe tape libraries to hold hundreds of terabytes (TB) of data spread across tens of thousands of tape volumes.
Virtual tape emulation (VTE) products such as DLm available from EMC is Corporation of Hopkinton, Mass. can be used to emulate a given number of tape volumes to the mainframe using disk drives as the storage media instead of magnetic tape. As a mainframe-based application writes data to what it believes is a tape drive, that data is actually stored as a tape volume image on direct access storage device such as a disk array subsystem system. Each individual tape volume written by the mainframe becomes a single disk file on the file system on the disk array.
Such VTE products ultimately allow the operators of mainframe data centers to move from a tape-based backup solution to a disk-based backup solution, leveraging today's high speed low cost disk technology to provide an innovative approach to data storage.
Guaranteed replication is an important feature of most modern disk-based file storage systems. Replication is a process that occurs typically in the background from the perspective of an application program, whereby mass storage devices such as disk arrays are backed up to a secondary storage media that may be local to or remote from this primary media.